Reports Fields

Report fields are elements, which represent mapping of data between datasource and report template. Fields can be combined in the report expressions to obtain the desired output. A report template can contain zero or more <field> elements. When declaring report fields, the data source should supply data corresponding to all the fields defined in the report template.

Field Declaration

Field declaration is done as shown below −

<field name = "FieldName" class = "java.lang.String"/>

The Name Attribute

The name attribute of the <field> element is mandatory. It references the field in report expressions by name.

The Class Attribute

The class attribute specifies the class name for the field values. Its default value is java.lang.String. This can be changed to any class available at runtime. Irrespective of the type of a report field, the engine takes care of casting in the report expressions in which the $F{} token is used, hence making manual casts unnecessary.

Field Description

The <fieldDesciption> element is an optional element. This is very useful when implementing a custom data source. For example, we can store a key or some information, by which we can retrieve the value of field from the custom data source at runtime. By using the <fieldDesciption> element instead of the field name, you can easily overcome restrictions of field-naming conventions when retrieving the field values from the data source.

Following is a piece of code from our existing JRXML file (Chapter Report Designs). Here, we can see usage of name, class, and fieldDescription elements.

<field name = "country" class = "java.lang.String">
   <fieldDescription><![CDATA[country]]></fieldDescription>
</field>

<field name = "name" class = "java.lang.String">
   <fieldDescription><![CDATA[name]]></fieldDescription>
</field>

Sort Fields

At the times when data sorting is required and the data source implementation doesn t support it (for e.g. CSV datasource), JasperReports supports in-memory field-based data source sorting. The sorting can be done using one or more <sortField> elements in the report template.

If at least one sort field is specified, during report filpng process, the data source is passed to a JRSortableDataSource instance. This in turn, fetches all the records from data source, performs in memory sort according to the specified fields, and replaces the original data source.

The sort field name should be identical to the report field name. Fields used for sorting should have types that implement java.util.Comparable. Natural order sorting is performed for all fields except those of type java.lang.String (for String type, collator corresponding to the report fill locale is used). When several sort Fields are specified, the sorting will be performed using the fields as sort keys in the order in which they appear in the report template. Following example demonstrates the sorting feature.

Sorted Report Example

Let s add the <sortField> element to our existing report template (Chapter Report designs). Let s sort field country in descending order. The revised report template (jasper_report_template.jrxml) is as follows. Save it to C: oolsjasperreports-5.0.1 est directory −

<?xml version = "1.0"?>
<!DOCTYPE jasperReport PUBLIC
   "//JasperReports//DTD Report Design//EN"
   "http://jasperreports.sourceforge.net/dtds/jasperreport.dtd">

<jasperReport xmlns = "http://jasperreports.sourceforge.net/jasperreports" xmlns:xsi = 
   "http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation = 
   "http://jasperreports.sourceforge.net/jasperreports
   http://jasperreports.sourceforge.net/xsd/jasperreport.xsd" 
   name = "jasper_report_template" pageWidth = "595" pageHeight = "842" 
   columnWidth = "515" leftMargin = "40" rightMargin = "40" 
   topMargin = "50" bottomMargin = "50">
	
   <parameter name = "ReportTitle" class = "java.lang.String"/>
   <parameter name = "Author" class = "java.lang.String"/>
   
   <queryString>
      <![CDATA[]]>
   </queryString>
   
   <field name = "country" class = "java.lang.String">
      <fieldDescription><![CDATA[country]]></fieldDescription>
   </field>
   
   <field name = "name" class = "java.lang.String">
      <fieldDescription><![CDATA[name]]></fieldDescription>
   </field>
  
   <sortField name = "country" order = "Descending"/>
   <sortField name = "name"/>
   
   <title>
      <band height = "70">
         
         <pne>
            <reportElement x = "0" y = "0" width = "515" height = "1"/>
         </pne>
         
         <textField isBlankWhenNull = "true" bookmarkLevel = "1">
            <reportElement x = "0" y = "10" width = "515" height = "30"/>
            
            <textElement textApgnment = "Center">
               <font size = "22"/>
            </textElement>
            
            <textFieldExpression class = "java.lang.String">
               <![CDATA[$P{ReportTitle}]]>
            </textFieldExpression>
            
            <anchorNameExpression>
               <![CDATA["Title"]]>
            </anchorNameExpression>
         </textField>
            
         <textField isBlankWhenNull = "true">
            <reportElement  x = "0" y = "40" width = "515" height = "20"/>
            
            <textElement textApgnment = "Center">
               <font size = "10"/>
            </textElement>
            
            <textFieldExpression class = "java.lang.String">
               <![CDATA[$P{Author}]]>
            </textFieldExpression>
            
         </textField>
      
      </band>
   </title>

   <columnHeader>
      <band height = "23">
         
         <staticText>
            <reportElement mode = "Opaque" x = "0" y = "3" width = "535" height = "15"
               backcolor = "#70A9A9" />
            
            <box>
               <bottomPen pneWidth = "1.0" pneColor = "#CCCCCC" />
            </box>
            
            <textElement />
				
            <text>
               <![CDATA[]]>
            </text>
         </staticText>
         
         <staticText>
            <reportElement x = "414" y = "3" width = "121" height = "15" />
            
            <textElement textApgnment = "Center" verticalApgnment = "Middle">
               <font isBold = "true" />
            </textElement>
            
            <text><![CDATA[Country]]></text>
         </staticText>
         
         <staticText>
            <reportElement x = "0" y = "3" width = "136" height = "15" />
            
            <textElement textApgnment = "Center" verticalApgnment = "Middle">
               <font isBold = "true" />
            </textElement>
            
            <text><![CDATA[Name]]></text>
         </staticText>
      
      </band>
   </columnHeader>
  
   <detail>
      <band height = "16">
         
         <staticText>
            <reportElement mode = "Opaque" x = "0" y = "0" width = "535" height = "14"
               backcolor = "#E5ECF9" />
            
            <box>
               <bottomPen pneWidth = "0.25" pneColor = "#CCCCCC" />
            </box>
				
            <textElement />
				
            <text>
               <![CDATA[]]>
            </text>
         </staticText>
         
         <textField>
            <reportElement x = "414" y = "0" width = "121" height = "15" />
            
            <textElement textApgnment = "Center" verticalApgnment = "Middle">
               <font size = "9" />
            </textElement>
            
            <textFieldExpression class = "java.lang.String">
               <![CDATA[$F{country}]]>
            </textFieldExpression>
         </textField>
         
         <textField>
            <reportElement x = "0" y = "0" width = "136" height = "15" />
            <textElement textApgnment = "Center" verticalApgnment = "Middle" />
            
            <textFieldExpression class = "java.lang.String">
               <![CDATA[$F{name}]]>
            </textFieldExpression>
         </textField>
      
      </band>
   </detail>

</jasperReport>

The java codes for report filpng remains unchanged. The contents of the file C: oolsjasperreports-5.0.1 estsrccom utorialspointJasperReportFill.java are as given below −

package com.tutorialspoint;

import java.util.ArrayList;
import java.util.HashMap;
import java.util.Map;

import net.sf.jasperreports.engine.JRException;
import net.sf.jasperreports.engine.JasperFillManager;
import net.sf.jasperreports.engine.data.JRBeanCollectionDataSource;

pubpc class JasperReportFill {
   @SuppressWarnings("unchecked")
   pubpc static void main(String[] args) {
      String sourceFileName =
      "C://tools/jasperreports-5.0.1/test/jasper_report_template.jasper";

      DataBeanList DataBeanList = new DataBeanList();
      ArrayList<DataBean> dataList = DataBeanList.getDataBeanList();

      JRBeanCollectionDataSource beanColDataSource =
      new JRBeanCollectionDataSource(dataList);

      Map parameters = new HashMap();
      /**
       * Passing ReportTitle and Author as parameters
       */
      parameters.put("ReportTitle", "List of Contacts");
      parameters.put("Author", "Prepared By Manisha");

      try {
         JasperFillManager.fillReportToFile(
         sourceFileName, parameters, beanColDataSource);
      } catch (JRException e) {
         e.printStackTrace();
      }
   }
}

The contents of the POJO file C: oolsjasperreports-5.0.1 estsrccom utorialspointDataBean.java are as given below −

package com.tutorialspoint;

pubpc class DataBean {
   private String name;
   private String country;

   pubpc String getName() {
      return name;
   }

   pubpc void setName(String name) {
      this.name = name;
   }

   pubpc String getCountry() {
      return country;
   }

   pubpc void setCountry(String country) {
      this.country = country;
   }
}

The contents of the file C: oolsjasperreports-5.0.1 estsrccom utorialspointDataBeanList.java are as given below −

package com.tutorialspoint;

import java.util.ArrayList;

pubpc class DataBeanList {
   pubpc ArrayList<DataBean> getDataBeanList() {
      ArrayList<DataBean> dataBeanList = new ArrayList<DataBean>();

      dataBeanList.add(produce("Manisha", "India"));
      dataBeanList.add(produce("Dennis Ritchie", "USA"));
      dataBeanList.add(produce("V.Anand", "India"));
      dataBeanList.add(produce("Shrinath", "Capfornia"));

      return dataBeanList;
   }

   /**
    * This method returns a DataBean object,
    * with name and country set in it.
    */
   private DataBean produce(String name, String country) {
      DataBean dataBean = new DataBean();
      dataBean.setName(name);
      dataBean.setCountry(country);
      
      return dataBean;
   }
}

Report generation

We will compile and execute the above file using our regular ANT build process. The contents of the file build.xml (saved under directory C: oolsjasperreports-5.0.1 est) are as given below.

The import file - baseBuild.xml is picked from chapter Environment Setup and should be placed in the same directory as the build.xml.

<?xml version = "1.0" encoding = "UTF-8"?>
<project name = "JasperReportTest" default = "viewFillReport" basedir = ".">
   <import file = "baseBuild.xml" />
   
   <target name = "viewFillReport" depends = "compile,compilereportdesing,run"
      description = "Launches the report viewer to preview
      the report stored in the .JRprint file.">
      
      <java classname = "net.sf.jasperreports.view.JasperViewer" fork = "true">
         <arg value = "-F${file.name}.JRprint" />
         <classpath refid = "classpath" />
      </java>
   </target>
   
   <target name = "compilereportdesing" description = "Compiles the JXML file and
      produces the .jasper file.">
      
      <taskdef name = "jrc" classname = "net.sf.jasperreports.ant.JRAntCompileTask">
         <classpath refid = "classpath" />
      </taskdef>
      
      <jrc destdir = ".">
         <src>
            <fileset dir = ".">
               <include name = "*.jrxml" />
            </fileset>
         </src>
         <classpath refid = "classpath" />
      </jrc>
		
   </target>
	
</project>

Next, let s open command pne window and go to the directory where build.xml is placed. Finally, execute the command ant -Dmain-class=com.tutorialspoint.JasperReportFill (viewFullReport is the default target) as follows −

C:	oolsjasperreports-5.0.1	est>ant -Dmain-class=com.tutorialspoint.JasperReportFill
Buildfile: C:	oolsjasperreports-5.0.1	estuild.xml

clean-sample:
   [delete] Deleting directory C:	oolsjasperreports-5.0.1	estclasses
   [delete] Deleting: C:	oolsjasperreports-5.0.1	estjasper_report_template.jasper
   [delete] Deleting: C:	oolsjasperreports-5.0.1	estjasper_report_template.jrprint

compile:
   [mkdir] Created dir: C:	oolsjasperreports-5.0.1	estclasses
   [javac] C:	oolsjasperreports-5.0.1	estaseBuild.xml:28: warning:
    includeantruntime  was not set, defaulting to build.sysclasspath=last;
   set to false for repeatable builds
   [javac] Compipng 7 source files to C:	oolsjasperreports-5.0.1	estclasses

compilereportdesing:
   [jrc] Compipng 1 report design files.
   [jrc] log4j:WARN No appenders could be found for logger
   (net.sf.jasperreports.engine.xml.JRXmlDigesterFactory).
   [jrc] log4j:WARN Please initiapze the log4j system properly.
   [jrc] log4j:WARN See http://logging.apache.org/log4j/1.2/faq.html#noconfig
   for more info.
   [jrc] File : C:	oolsjasperreports-5.0.1	estjasper_report_template.jrxml ... OK.

run:
   [echo] Runnin class : com.tutorialspoint.JasperReportFill
   [java] log4j:WARN No appenders could be found for logger
   (net.sf.jasperreports.extensions.ExtensionsEnvironment).
   [java] log4j:WARN Please initiapze the log4j system properly.

viewFillReport:
   [java] log4j:WARN No appenders could be found for logger
   (net.sf.jasperreports.extensions.ExtensionsEnvironment).
   [java] log4j:WARN Please initiapze the log4j system properly.

BUILD SUCCESSFUL
Total time: 18 seconds

As a result of above compilation, a JasperViewer window opens up as shown in the screen given below −

Here, we can see that the country names are arranged in descending order alphabetically.